The aim of the project is to write a comprehensive biography of the physician S.A.A.D. Tissot (1728-1797). The Protestant French-speaking Swiss Tissot acquired European fame with his writings on health and by his clinical teaching at Pavia. He was a disciple of the Montpellier School (student of Boissier de Sauvages), a friend of the Philosophers (correspondent of Rousseau and Voltaire) and well versed in the achievements of British medicine. The books of Cullen, Duncan, Hunter(s), Monro(s), Pringle, among many others are listed in his library catalog. The writers of the Enlightenment influenced a change of mentality in many fields (politics, education, science,...) and medicine was no exception. The published and unpublished writings of Tissot will serve as a case-study to demonstrate this change. His life and works illustrate the emerging mentality and its consequences for the field of health-care, clinical teaching, and public health. His medical thought is fruit of the medical enlightenment of the 18th century and seed for the 19th century medical revolution. While Tissot is often referred to for his books: Avis au peuple (1761), L'Onanisme (1760) and Traite des nerfs (1780) as seminal to the thought of others (e.g. Buchan, Frank, Pinel), his role in defense of inoculation or in the development of clinical teaching is less known, if not ignored by most historians of medicine. No comprehensive study of Tissot has ever been published since the 1830s when Eynard wrote his Essai sur la vie de Tissot. The core of my research on Tissot is contained in my dissertation. I used there his published books and his voluminous personal papers to document my study. My methodology is to consider Tissot's writings comprehensively by subjects treated and chronological order to study influences on and by others, and the evolution of his medical philosophy, within the main stream of European medicine (e.g. Bordeu, Haller, van Swieten). My thorough knowledge of European history (in particular Switzerland), of the French language, and of the Protestant mentality, allows me a sensitive approach and a deep understanding of the documents considered and the milieu of their writings. I have readily access to the archives in Switzerland, which I have used extensively in several past research trips, and thus have acquired an accurate knowledge of their holdings. I own most of Tissot's books and have already accumulated a substantial collection of copies of his manuscripts or of extensive notes about them.